The invention relates to organic polymers carrying active groups chemically fixed to the polymer chain, these groups having specific properties, particular examples being chromophoric, tensio-active, ion exchange, cosmetological, rheological, chelating or other groups. The invention includes the uses of polymers provided with such groups, in particular for the preparation of pigments, varnishes, paints, ion exchange resins, cosmetic products, chromatographic supports and so on.
In order to provide simplification, the following part of the present description relates mainly to cosmetic agents which illustrate the invention, but it is to be understood however that the invention is applicable to other areas of use, because the active cosmetological groups can be replaced in analogous fashion by other active groups.
For several years, there has been a tendency in cosmetology to utilize various active substances, not only as such, in an appropriate excipient, but also by fixing them to macromolecules. The main reason for this is that the skin tends to absorb various monomeric active compounds, which gives the disadvantage of removing a part of these compounds from the surface of the skin where their action should occur. On the other hand, penetration into the organism can be prejudicial to health in many cases. This penetration can be considerably diminished or even totally prevented, if the active substance is in the form of a polymer of sufficiently large molecular dimensions. Various polymers have thus been employed for this purpose, particularly polyacrylates, polymethacrylates and their copolymers, especially those with vinyl-pyrrolidone, the polyoxyalkylenes and so on. The important point of this technique is the manner in which the active cosmetological groups are attached to the polymer chain. This has been realised previously through the intermediary of two conjugated carboxylic groups: ##STR1## according to French Patent Specification No. 73 23704, or by means of an imide group: ##STR2## as described in French Patent Application No. 76 23174. However, this technique still needs to be perfected. It is necessary for the activity of the groups concerned not to undergo too great a reduction by reason of their combination with the polymer and that the product can exhibit the requisite solubility for its intended use.